Reliability of the ultrasound classification system of thyroid nodules in predicting malignancy

ABSTRACT

Aim: This study aims to evaluate the reliability of theUltrasound (U) Classification system in predicting thyroidmalignancy by using pathology diagnosis as the referencestandard.Methods: It was a cross-sectional study carried out atUniversiti Kebangsaan Malaysia Medical Centre (UKMMC),Malaysia. Records of patients with focal thyroid nodules onultrasound (US) for which US-guided fine needle aspirationcytology (FNAC) was performed and pathology results wereavailable, from January 2014 to May 2016 were selected forreview. Correlation of the U Classification with pathologyresults was assessed. Sensitivity, specificity, positivelikelihood ratio, negative likelihood ratio, predictive value,negative predictive value and accuracy were calculated in aconservative and non-conservative method. The thresholdfor statistical performance was set at 0.05. Eachsonographic feature was also compared with its pathologyresults.Results: A total of 91 patients with 104 nodules were eligible.12 nodules out of 104 (11.5%) were malignant. Thesensitivity, specificity, positive likelihood ratio, negativelikelihood ratio, positive predictive value, negativepredictive value and accuracy were 100%, 91.3%, 11.5, 0.0,60%, 100% and 92.3%, and 100%, 91.4%, 11.7%, 0.0, 78.6%,100% and 93.5%, for the non-conservative and conservativemethod of calculations respectively.Conclusion: The U Classification is reliable in predictingthyroid malignancy. More evidence is neverthelessnecessary for widespread adaptation and use.